Conventionally, a plate mounting device equipped with a plate cylinder is known. The plate cylinder is formed in a cylindrical shape and mounted on a plate driving shaft in a fixed manner. The plate cylinder is configured to mount a cylindrically formed printing plate from the tip end side of the plate cylinder on an outer peripheral surface thereof.
Patent Document 1 discloses a plate cylinder. The plate cylinder is equipped with a recess and a plate fixing member. The recess is formed in an elongated rectangular shape extending in the axial direction over the large part of the axial length of the plate cylinder and has a rectangular cross-sectional shape. The plate fixing member is configured to push a non-plate portion of a plate mounted on a plate cylinder portion from a radially inner side toward a radially outer side to thereby closely fix the plate to a plate mounting surface of the plate cylinder portion.
The plate fixing member is configured to be fitted in the recess substantially with no gap in the circumferential direction and the axial direction thereof so as to move in a radial direction of the plate cylinder along both circumferential side walls and both axial end walls of the recess.